21st Century Fate of the Mocho-Choshuenco Ice Cap in Southern Chile
Abstract
We apply the ice sheet model SICOPOLIS to the Mocho-Choshuenco ice cap in the Chilean Lake District (40ºS) to investigate its evolution until the end of the 21st century. On the ice cap, a large amount of field data including surface mass balance and ice thickness has been collected during the last 15 years, making it a valuable study object. Like the great majority of glaciers in southern Chile and Argentina, the ice cap has experienced high rates of thinning and retreat in the recent past. This process has been primarily attributed to increasing atmospheric temperatures and for the near future, further global warming and subsequent further ice losses are expected.
The Mocho-Choshuenco ice cap is by far the smallest cryospheric object studied until now by SICOPOLIS. The shallow ice approximation incorporated by the model poses major challenges when applying it to an ice cap of such a small size, especially at steep slopes. However, it proves to work sufficiently well on most parts of the ice cap. First, we create a model spin-up under constant temperatures representing current climatic conditions using a newly developed parametrization accounting for small-scale variations of the surface mass balance. The present-day shape of the ice cap can be reproduced well by this spin-up. Then, we run the model 80 years into the future, forced by predicted surface temperature anomalies under the RCP2.6 and RCP8.5 scenarios to obtain estimates of the ice cap state by the end of the 21st century. Depending on the scenario, a medium to high ice mass loss is predicted, with the possibility of almost complete glacier disappearance until the year 2100 under the pessimistic RCP8.5 scenario (see figure for 2005-2065).- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C31B1510S
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0762 Mass balance;
- CRYOSPHERE;
- 0776 Glaciology;
- CRYOSPHERE